SELECTION WITHIN PURE LINES OF PESTALOZZIA 



155 



All the plates from the three different cultures were poured on the same 

 day, and from agar of the same lot. All the spore transfers were made 

 on the same day and all were kept in the same rack under the same 

 environmental conditions. Whatever the influences of environment were 

 they would act on all the cultures in the same way, and such variations 

 as might occur between cultures would therefore be ascribed to heredity. 



Some variation in time of sporulation was always found but no definite 

 correlation was noted between the characters studied and the relative 

 rapidity of development. It was found that the difference in size between 



TABLE 2 



Comparison of spore appendage lengths of early and late spores from the same culture. (Strain 

 29, experiment 2, generation 17, plus-selected group, culture 3.} Lengths in ju. 



the spores first developed in a culture and those developed several days 

 later was not significant when compared with the differences which were 

 usually found between different cultures. 



This fact is shown in table 2 where distributions of measurements of 

 early and late spores from the same culture are given. The early spores 

 were taken when only a few had been formed, the late spores were the last 

 of which the time of formation was definitely known. It should be noted 

 that all the spores measured here, as in all other parts of this investiga- 

 tion, were mature normal spores, being fully septate and having three 



GENETICS 7: Mr 1922 



